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2
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bit_stream = [ 0 0 0 0 1 1 0 0 0 1 0]; 
no_bits = length(bit_stream);
bit_rate = 2000;
pulse_per_bit = 2;
pulse_duration = 1/((pulse_per_bit)*(bit_rate));
no_pulses = no_bits*pulse_per_bit; 
samples_per_pulse = 500;
fs = (samples_per_pulse)/(pulse_duration); 
t = 0:1/fs:(no_pulses)*(pulse_duration); 
no_samples = length(t);
dig_sig = zeros(1,no_samples); 
max_voltage = +2;
min_voltage = -2;
inv_bit = 1;
last_state = max_voltage; 
inv_last_state = min_voltage; 
for i = 1:no_bits
    j = (i-1)*2;
    if bit_stream(i) == inv_bit

dig_sig((j*(samples_per_pulse)+1):(j+1)*(samples_per_pulse)) = inv_last_state*ones(1,samples_per_pulse);
 
dig_sig(((j+1)*(samples_per_pulse)+1):(j+2)*(samples_per_pulse)) = last_state*ones(1,samples_per_pulse);
    else

dig_sig((j*(samples_per_pulse)+1):(j+1)*(samples_per_pulse)) = last_state*ones(1,samples_per_pulse);

dig_sig(((j+1)*(samples_per_pulse)+1):(j+2)*(samples_per_pulse)) = inv_last_state*ones(1,samples_per_pulse);
          temp_cons = last_state; % temporary constant 
          last_state = inv_last_state;
inv_last_state = temp_cons; 
    end
 end 
figure
plot(t,dig_sig,'LineWidth',1.5) 
grid on
xlabel('time in seconds') 
ylabel('voltage')
ylim([(min_voltage-(max_voltage)*0.2)*(max_voltage+max_voltage*0.2)]) 
title(['Differential manchester for',num2str(bit_stream)' '])